Convert all shapes to use unit_mode only

[pvnbhargava]

We would like to reduce the confusion and errors caused by accidentally using unit_mode and non-unit_mode values together. These can cause incompatibilities that are difficult to debug and resolve.

The tentative solution is to have all Photonic Objects assume that they are getting unit-mode values by default. It will be the job of PhotonicTemplateBase to convert non-unit mode values to unit-mode before creating objects. Note that Photonic Objects must still carry information about the resolution value and must be able to return non-unit mode values if prompted.